Taiwan Utility Model Publication No. 354932 discloses a reversible high-torque screwdriver comprising a handle, a mounting seat fixed to an end of the handle, a gear wheel mounted in a longitudinal blind hole defined in the mounting seat, and a bit mounted to a square coupling hole defined in a side of the gear wheel. A pawl is received in a groove in the mounting seat and includes a first toothed section and a second toothed section for selective engagement with teeth on an outer periphery of the gear wheel. The pawl can be moved by a switch member that comprises a disc to which an elastic element is mounted. The first toothed section of the pawl is disengaged from the gear wheel, and the second toothed section is engaged with the gear wheel to allow the screwdriver to drive a fastener or the like in a first direction and to turn freely in a second direction opposite to the first direction. The position of the pawl can be switched by the switch member such that the first toothed section of the pawl is engaged with the gear wheel and that the second toothed section of the pawl is disengaged from the gear wheel to allow the screwdriver to drive the fastener in the second direction and to turn freely in the first direction.
The mounting scat has a complicated shape and a small size and is thus difficult to process. To solve this problem, the mounting seat is generally formed of zinc alloy by injection molding. The wall delimiting the groove of the mounting seat could only bear low torque imparted by the pawl, as zinc alloy is not strong. When high torque is applied to the screwdriver, the pawl made of rigid material would cause deformation or fracture of the wall delimiting the groove of the mounting seat, resulting in malfunction of the screwdriver. Namely, the screwdriver in fact could not provide high-torque operation. Similar problems exist in Taiwan Utility Model Publication Nos. 527993 and M241178.